Hinged window for an x-ray analyzer chamber

ABSTRACT

An X-ray chamber having an aperture in a wall closed by a hinged window controlled by an actuating member so as to form a vacuum seal in the closed position.

United States Patent [72] Inventor George William Browning Sale, England [21 Appl. No. 689,642

[22] Filed Dec. 11,1967

[45 Patented Feb. 23, 1971 [73] Assignee Associated Electrical Industries Limited London, England [32] Priority Dec. 13,1966

[3 3 Great Britain [54] l-llNGED WINDOW FOR AN X-RAY ANALYSER CHAMBER 10 Claims, 4 Drawing Figs.

[52] US. Cl 250/86, 250/51.5, 250/90, 250/105, 313/59 [51] Int. Cl H0lj 5/16, l-lOlj 5/18 [50] Field ofSearch 250/51.5, 86, 90, 105; 313/59, 74; 356/246 [56] References Cited UNITED STATES PATENTS 3,319,064 5/1967 Guernet et al. 250/49.5 3,409,769 11/1968 McKinney et a1 250/51.5

Primary ExaminerRalph G. Nilson Assistant Examiner-A. L. Birch Attorney-Watts, Hoffmann, Fisher & Heinke ABSTRACT: An X-ray chamber having an aperture in a wall closed by a hinged window controlled by an actuating member so as to form a vacuum seal in the closed position.

PATENTE-D' FEB 2 3127:

SHEET 1 or 2" INVENTOR GEORGE WILLIAM BROWNING BY i J A TTORNEYS memmmzsmn 3566,1213

SHEET 2 BF 2 FIGZ INVENTOR GEORGE WILLIAM BROWNING BY 9741/6176? nd; 5%

A T TORNEYS HINGED WINDOW FOR AN X-RAY ANALYSER CHAMBER This invention relates to X-ray and gamma ray apparatus and has an important application in X-ray analyzers.

When a solid is bombarded with electrons to cause it to emit X-rays the wavelength of the X-rays will depend upon the material from which they are emitted. In an .X-ray analyzer this property is utilized by projecting the X-rays on to a crystal which reflects them on to a radiation detector. By measuring the angle of reflection, which will depend on the wavelength, it is possible to analyze the material under examination.

The electron bombardment normally takes place in a specimen chamber which is under vacuum and is sealed to prevent the escape of electrons which might be detrimental to the measurement and the X-rays are allowed to emerge through a window which is transparentto X-rays but is sealed against the escape of stray electrons. This is perfectly suitable when dealing with the shorter wavelength X-rays but when dealing with longer wavelength X-rays these are absorbed by the window even ifvery thin. It follows therefore that in apparatus covering a wide range of wavelengths, especially in apparatus in which provision is made for crystal changing it is desirable there should also be provision for removing the covering of the X-ray window at will to allow the longer wavelength X-rays free passage. The effect of the escape of the electrons can be reduced markedly by the introduction of an electron trap and collimator system (not shown). Other applications are also arise in which it is required to open or close at will a window through which X-rays are projected.

The construction of a window with a removable cover presents difficulties since it is desirable to exert sufficient pressure in the closed position to effecta satisfactory vacuum seal against vacuum pressures which can be applied to either or both sides of the window whilst at the same time the operating effort should be kept small.

A sliding cover requires a considerable amount of space which is not readily available and moreover it is liable to cut sealing rings arranged around the aperture.

A hinged window which is pivotally operated would allow the window to be uncovered but it would require considerable effort to produce the pressure necessary to seal the aperture when in the closed position. The main object of the invention is to provide an improved construction which avoids the above disadvantages.

According to the present invention an X-ray chamber is formed with a wall having an aperture and is provided with a hinged cover having a ramp surface and a projecting arm, together with an actuating member movable along guides between positions in which the cover is open and closed respectively. The arrangement is such that when moved to the closed position, the actuating member moves over the ramp surface so as to exert pressure between the guide and the cover and thereby press the cover against the wall surrounding the aperture. When the actuating member is moved to the open position it abuts against the arm to rotate the cover about its hinge away from the aperture.

Preferably the actuating member is coupled through a link with a bellcrank lever, rotation of which lever moves the actuating member along the guide between the open and closed positions and vice versa.

In order that the invention may be more clearly understood reference will now be made to the accompanying drawing in which:

FIG. 1 is a front view of a wall of an X-ray chamber having a hinged closure member for a window constructed in accordance with the invention,

FIG. 2 is a section on the line II-II of FIG. 1,

FIG. 3 is a section on the line III-III of FIG. 1, and

FIG. 4 is a perspective view of a closure member embodying the invention.

In the drawing the reference numeral 1 indicates generally the wall of anX-ray chamber. This is formed with a window 2 which is elongated horizontally. The cover is indicated generally by the reference numeral 3 and is pivotal about horizontal rods 4 at each end of the cover. The rods 4 project rom the ends of the cover and are mounted in fixed end walls 20 of the illustrated structure. In the arrangement shown the cover 3 is also formed with an aperture 5 which in the closed position is aligned with the aperture 2 and is covered with a thin membrane 6 of a suitable plastic material such as melinex. FIG. 3 shows the closed position of the cover and will be seen that is presses against a sealing ring 7. Opening and closing of the cover,is effected by the horizontal bar 8. The ends of the bar 8 slide in vertical slots 9 formed in strips 10 at each end of the apparatus as shown. The rod 8 is carried in the forked ends 11 of an actuating member 12 having an arm 13 extending upwardly and pivoted at 14 to a bellcrank lever 15 mounted on a shaft 16. It will be readily seen that rotation of the bellcrank lever 15 raises and lowers the actuatingmember l2 and hence raises andlowers the bar 8 which as above stated runs in the guide slots 9. When the bar 8 is lowered to the position shown inFlG. 3 it will be seen that the bar 8 slides over the ramp surface 17 formed on the cover 3 and presses the cover against the sealing ring 7. When the bellcrank lever 15 however is rotating clockwise it will raise the bar 8 away from the ramp surface 17 and will eventually abut against the surfaces 18 formed on the underside of the arms 19 extending radially outwards from the pivot 4 of the cover-3., This .will rotate the cover about its pivot 4 of the coveruntil it isclear ofthe aperture 2 and thus allow free communication between the opposite sides of the wall I.

It will be readily appreciated that such an arrangement is simple and robust and enables a high pressure to be exerted on the sealing ring with a relatively small effort.

Whilst in the arrangement shown the aperture 5 in the cover is covered with an X-ray transparent material, the aperture can, in some constructions be omitted so that in the closed position the X-rays are blocked.

Iclaim:

1. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising:

a. movable cover means for said aperture;

b. actuating means operatively connected to said cover means;

c. said actuating means including a cover-engaging member;

and

d. means mounting said actuating means for movement between a first position in which said member exerts pressure on a first portion of said cover means to press said cover means into sealing engagement .with said wall around said aperture and a second position in which said member abuts a second portion of said cover means to move said cover means away from said aperture.

2. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising:

a. movable cover means for said aperture;

b. actuating means operatively connected to said cover means;

c. said actuating means including a cover-engaging member;

d. guide means mounting said actuating means for movement of said member relative to said cover means;

e. said cover-engaging member being movable between a first position in which said member exerts pressure against a first portion of said cover means to press said cover means toward said wall over said aperture and a second position in which said member abuts a second portion of said cover means to move it away from said aperture; and

f. sealing means forming a vacuum seal between said cover means and said wall around said aperture in said first position of said member.

3. The improvement as claimed in claim 2 wherein said cover means includes an opening alignable with said aperture, and means transparent to X-rays extending over said opening.

4. The improvement as claimed in claim 2 wherein said first portion of said cover means is a ramp surface.

5. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising:

a. a hingedly mounted cover for said aperture including an abutment portion anda ramp surface;

b. said cover being movable between a closed position over said aperture and an open position spaced from said aperture;

c. means forming a-seal between said cover and said wall around said aperture in said closed position; and

d. cover actuating means including a movable member selectively engageable with said ramp surface to press said cover in sealing engagement around said aperture and with said abutment portion to rotate said cover away from said aperture.

6. The improvement as claimed in claim 5 wherein said cover means includes an opening alignable with said aperture, and means transparent to X rays extending over said opening.

7. The improvement as claimed in claim5 including guide means mounting said member for reciprocal movement.

8. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising:

a. cover means for said aperture;

b. said cover means being movable between a closed position in which said cover means is sealed against said wall around said aperture and an open position in which said cover means is spaced from said aperture;

c. cover actuating means including a rotatable shaft, a cover-engaging member, and means connecting said member to said shaft; and

d. guide means mounting said member for reciprocal movement between a first position in which said member presses against a first portion of said cover means to place it in said closed position and a second position in which said member abuts a second portion of said cover to move it to said open position.

9. In an apparatus including an X-ray chamber having a wall which includes an aperture,-the improvement comprising:

a. a hingedly mounted cover for said aperture including an abutment portion and a ramp surface;

b. said cover being movable between a closed position over said aperture and an open position spaced from said aperture;

c. means forming a seal between said cover and said wall around said aperture in said closed position;

d. cover actuating means including a rotatable shaft. u cover-engaging member, and means connecting said member to said shaft; and

e. guide means mounting said member for reciprocal movement between a first position in. which said member presses against said ramp surface to place said cover in said closed position and a second position in which said member engages said abutment portion to rotate said cover away from said aperture to said open position.

10. The improvement as claimed in claim 9 wherein said cover includes an opening alignable with said aperture in said closed position, and a sheet of material transparent to X-rays extending across said cover opening and forming a vacuum seal therewith. 

1. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising: a. movable cover means for said aperture; b. actuating means operatively connected to said cover means; c. said actuating means including a cover-engaging member; and d. means mounting said actuating means for movement between a first position in which said member exerts pressure on a first portion of said cover means to press said cover means into sealing engagement with said wall around said aperture and a second position in which said member abuts a second portion of said cover means to move said cover means away from said aperture.
 2. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising: a. movable cover means for said aperture; b. actuating means operatively connected to said cover means; c. said actuating means including a cover-engaging member; d. guide means mounting said actuating means for movement of said member relative to said cover means; e. said cover-engaging member being movabLe between a first position in which said member exerts pressure against a first portion of said cover means to press said cover means toward said wall over said aperture and a second position in which said member abuts a second portion of said cover means to move it away from said aperture; and f. sealing means forming a vacuum seal between said cover means and said wall around said aperture in said first position of said member.
 3. The improvement as claimed in claim 2 wherein said cover means includes an opening alignable with said aperture, and means transparent to X-rays extending over said opening.
 4. The improvement as claimed in claim 2 wherein said first portion of said cover means is a ramp surface.
 5. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising: a. a hingedly mounted cover for said aperture including an abutment portion and a ramp surface; b. said cover being movable between a closed position over said aperture and an open position spaced from said aperture; c. means forming a seal between said cover and said wall around said aperture in said closed position; and d. cover actuating means including a movable member selectively engageable with said ramp surface to press said cover in sealing engagement around said aperture and with said abutment portion to rotate said cover away from said aperture.
 6. The improvement as claimed in claim 5 wherein said cover means includes an opening alignable with said aperture, and means transparent to X-rays extending over said opening.
 7. The improvement as claimed in claim 5 including guide means mounting said member for reciprocal movement.
 8. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising: a. cover means for said aperture; b. said cover means being movable between a closed position in which said cover means is sealed against said wall around said aperture and an open position in which said cover means is spaced from said aperture; c. cover actuating means including a rotatable shaft, a cover-engaging member, and means connecting said member to said shaft; and d. guide means mounting said member for reciprocal movement between a first position in which said member presses against a first portion of said cover means to place it in said closed position and a second position in which said member abuts a second portion of said cover to move it to said open position.
 9. In an apparatus including an X-ray chamber having a wall which includes an aperture, the improvement comprising: a. a hingedly mounted cover for said aperture including an abutment portion and a ramp surface; b. said cover being movable between a closed position over said aperture and an open position spaced from said aperture; c. means forming a seal between said cover and said wall around said aperture in said closed position; d. cover actuating means including a rotatable shaft, a cover-engaging member, and means connecting said member to said shaft; and e. guide means mounting said member for reciprocal movement between a first position in which said member presses against said ramp surface to place said cover in said closed position and a second position in which said member engages said abutment portion to rotate said cover away from said aperture to said open position.
 10. The improvement as claimed in claim 9 wherein said cover includes an opening alignable with said aperture in said closed position, and a sheet of material transparent to X-rays extending across said cover opening and forming a vacuum seal therewith. 